This invention relates to devices for driving a flexible protection web adapted to be rolled and unrolled on and from a winding shaft. The free end of the web is connected through the medium of at least one flexible bond to the outer periphery of a winding drum.
In known devices of this character, for example the one described and illustrated in the French Patent No. 2,329,838, the winding drum is coaxial to, and rotatably solid with, the winding shaft. The flexible bonds connecting the end of the flexible web to the winding drum are guided by pulleys mounted for loose rotation on spring-loaded supports disposed on the side from which the flexible web is to be unrolled. The winding drum is so designed that its outer diameter increases as the flexible web is rolled up, so that the springs of the pulley carriers are gradually stressed and the flexible web is kept in its stretched condition throughout the unrolling thereof.
However, this device is objectionable in that its structure is relatively complicated and the flexible bonds disposed on either side of the flexible web during the rolling up thereof are cumbersome and rather unsightly. Moreover, fitting the guide pulleys and the flexible bonds constitutes a relatively long a tedious operation for a proper rolling up and off of the web.